Yes, given the downvotes, I fear my comment may be misconstrued as a function(al) bash. I write lots of Elixir these days. And see the same issues. All I was trying to say is that, my experience in OOland, that was hyper focused on this idea, gave me lots of opportunity to see that while this rule is obvious and good and everyone wants to do it, I observed that for many programmers decomposing complex data structures is a very non-intuitive task, and difficult to actually realize this rule.